A conventional image pickup apparatus includes a light receiving section such as a CCD (Charge Coupled Device) which has light receiving elements arranged in a matrix pattern. The light receiving section detects, as a large number of sample points, the object to be photographed or the image to be picked up. Output signals representing the individual sample points as detected form an image signal. Therefore, the resolution when the image is picked up is determined by the number of light receiving elements. Normally, in the case where the number of light receiving elements is increased, the cost of the CCD rises even though the integration density of the light receiving section is not increased. In order to improve the integration density without a change in the size of the area occupied by the light receiving section or the CCD, it is necessary to improve the manufacturing accuracy. This results in the cost of the CCD further rising.
A method proposed as means for solving the above will now be described. According to this method, the positions of the sample points with respect to the light receiving section are mechanically or optically changed in sequence. The sample points are detected by any one of the light receiving elements. The output signals corresponding to the detected sample points are output in synchronization with changes of the positions of the sample points, and as a result, a plurality of image signals are produced. In this method, the integration density need not be increased.
In the above method, the structure by which the light receiving section is moved lengthwise or widthwise may be used as means for mechanically moving the sample points. The structure by which the tilt angle, tilt direction, thickness, etc. of a light refracting element are changed may be used as means for optically moving the sample points.
The output signals serving the image signals and representing the sample points moved and detected by any one of the light receiving elements are subjected to the interpolation. The interpolation is the processing by which pixel data in the individual image signals produced in sequence are arranged at the middle portions of the light receiving elements of the CCD. Final pixel arrangement data is attained through the interpolation.
FIGS. 1A to 1D are diagrams showing examples of the interpolation for attaining the final pixel arrangement data.
In FIGS. 1A to 1D, color filters mounted on black masks are provided in front of the light receiving elements of the light receiving section. Each black mask is provided with apertures. Each aperture is formed so that the light passing therethrough is projected on the general center of its corresponding light receiving element. As shown in FIG. 1A, the light receiving section includes four apertures A, B, C and D which are arranged in 2xc3x972 matrix pattern. The apertures are in one-to-one correspondence with the light receiving elements. There is an interval equal to the length or width of 1 aperture between the apertures of each laterally or vertically adjacent pair among the apertures A to D.
Each light receiving element sequentially detects four sample points from the object to be photographed, and the interpolation is performed with respect to the image obtained as that of the object. For easy understanding, let it be assumed in the following explanation that the apertures located above the light receiving elements are moved.
First, as shown in FIG. 1B, the apertures A to D corresponding to the light receiving elements are moved 0.5 element pitch to the right. As a result, the aperture A is located adjacent to and on the right-hand side of its initial position. The aperture B is located adjacent to and on the right-hand side of its initial position. The aperture C is located adjacent to and on the right-hand side of its initial position. The aperture D is located adjacent to and on the right-hand side of its initial position.
Thereafter, as shown in FIG. 1C, the apertures A to D are moved 0.5 element pitch downward. In consequence, the, aperture A is located directly under the position which the aperture A has reached as a result of the previous movement. The aperture B is located directly under the position which the aperture B has reached as a result of the previous movement. The aperture C is located directly under the position which the aperture C has reached as a result of the previous movement. The aperture D is located directly under the position which the aperture D has reached as a result of the previous movement.
Thereafter, as shown in FIG. 1D, the apertures A to D are further moved 0.5 element pitch to the left. Consequently, the aperture A is located adjacent to and on the left-hand side of the position which the aperture A has reached as a result of the previous movement. The aperture B is located adjacent to and on the left-hand side of the position which the aperture B has reached as a result of the previous movement. The aperture C is located adjacent to and on the left-hand side of the position which the aperture C has reached as a result of the previous movement. The aperture D is located adjacent to and on the left-hand side of the position which the aperture D has reached as a result of the previous movement.
FIG. 1D shows the final pixel arrangement data attained in the above-described manner. In the final pixel arrangement data, the pixel data representing the light which has passed through the same aperture are arranged adjacent to each other. Specifically, of the pixel data, four pixel data items representing the light which has passed through the aperture A are arranged adjacent to each other, and four pixel data items representing the light which has passed through the aperture B are arranged adjacent to each other and on the right-hand side of the group formed of the pixel data items representing the light which has passed through the aperture A. Four pixel data items representing the light which has passed through the aperture C are arranged adjacent to each other and under the group formed of the pixel data items representing the light which has passed through the aperture A. Four pixel data items representing..the light which has passed through the aperture D are arranged adjacent to each other and under the group formed of the pixel data items representing the light which has passed through the aperture B. By processing the final pixel arrangement data described above, a luminance signal Y and color difference signals Rxe2x88x92Y and Bxe2x88x92Y are attained. The signals Y, Rxe2x88x92Y and Bxe2x88x92Y are reproduced as the final pixel arrangement data having the pixel arrangement shown in FIG. 1 D, whereby the picked-up image is reproduced. With this method, the resolution is improved without a change in the integration density of the light receiving elements.
However, according to the above method, as shown in FIG. 1D, the pixel data representing the light which has passed through the same aperture are adjacent to each other in the final pixel arrangement data. In that case, four kinds of pixel data representing the light which has passed through the apertures form groups according to the respective kinds. Under this condition, the resolution when a group of adjacent pixel data corresponding to the same color is regarded as a single pixel data item is not improved. Consequently, the data precision of the chrominance signal Y and the color difference signals Rxe2x88x92Y and Bxe2x88x92Y is low, and the horizontal and vertical resolutions are not satisfactorily improved. This prevents a conventional image pickup apparatus from having satisfactorily high performance.
According to one preferred embodiment of the present invention, there is provided an image pickup apparatus comprising:
a light receiving section having a plurality of groups each consisting of apertures and light receiving elements for receiving light coming from sample points on an object to be photographed and for outputting a signal representing the light, said apertures being orthographically projected in different positions on light receiving surfaces of said light receiving elements;
sample point changing means for changing a position in which the light coming from the sample points is projected on the light receiving surfaces of said light receiving elements;
image forming means for, in synchronization with changes of said position, receiving signals representing light which one of said light receiving elements has received sequentially from the sample points and for producing, from said signals, image signals including pixel data representing said light which one of said light receiving elements has received sequentially from the sample points; and
control means for apparently moving said apertures to predetermined positions on the light receiving surfaces of said light receiving elements, and for arranging, adjacent to each other, the pixel data representing the light which has passed through different apertures.
According to another preferred embodiment of the present invention, there is provided an image pickup apparatus comprising:
a light receiving section having a plurality of groups each consisting of apertures located in different positions and light receiving elements forming a set;
displacing means for changing a positional relationship between each of said light receiving elements and a light beam which enters each said light receiving element, an exposure of light to said light receiving section being performed a number of times, the number of light beams which enter each said light receiving elements being one per exposure, and said displacing means changing said positional relationship each time the exposure is performed;
storing means for receiving output signals representing the light beams which have entered each said light receiving element at times of the exposure and for storing said output signals in association with timings of the exposure; and
control means for producing image data from output signals stored in said storing means.
According to another preferred embodiment of the present invention, there is provided an image pickup apparatus comprising:
an image pickup section having a plurality of groups each consisting of image pickup elements including light detecting portions, located in different positions, for detecting intensities of light beams entering said light detecting portions;
shift means for changing a positional relationship between each of said light detecting portions and a light beam which enters each said light detecting portion, a detection of light being performed a number of times by each said light detecting portion, the number of light beams detected by each said light detecting portion being one per detection, and said shift means changing said positional relationship each time the detection is performed;
control means for producing image data from output signals representing the light beams detected by each said light detecting portion; and
storing means for storing the image data produced by said control means.
According to the above-described structure, any light receiving element of the light receiving section sequentially detects light representing sample points of the image of the object to be photographed, and a plurality of image signals are produced. This improves the resolution without having to change the integration density. The light receiving section includes sets of light receiving elements, and apertures are orthographically projected in different positions on the light receiving surfaces of the light receiving elements of each set. The apertures are apparently moved to predetermined positions on the light receiving surfaces. The pixel data as produced are arranged so that pixel data representing the intensity of light which has passed through different apertures are adjacent to each other. Therefore, with the final pixel arrangement attained by the aforementioned processing (interpolation) of arranging the pixel data, the resolution when a group of adjacent pixel data corresponding to the same color is regarded as a single pixel data item is improved (in other words, the final pixel arrangement is finer than that of the conventional case). The arrangement of the pixel data in the final pixel arrangement data after the interpolation is the same as that of the light receiving elements before the interpolation. Accordingly, the data precision of the luminance signal and the color difference signals is high. Moreover, the horizontal and vertical resolutions are improved. Under the above-described conditions, the performance of the image pickup apparatus is considerably improved.